The present invention relates to wipers for industrial and other applications involving the absorption of water, oil and other liquid materials. Such wipers can take the form of a fabric which can be used, for example, in maintenance shop, auto repair, and industrial facility cleanup, in hand wiping, and in any application in which it is desirable to have a single material that wipes well for both oil and water. Since wiping is, in most cases, performed by hand, it is desired to obtain a wiper that wipes clean with a minimum effort, preferably on the first application. Most paper wipers, while inexpensive, are only effective for a single use and then must be disposed. Cloth wipers, which are most often used in industrial applications, are expensive and therefore must be reused for economy, and also must be laundered. It is therefore desirable to obtain a low-cost wiper with high absorbability that is durable and thus can be used more than once and then disposed.
As disclosed in U.S. Pat. No. 4,307,143, many forms of wipers are available for various applications. In general, however, prior wipers can be classified as either paper or cloth. Paper wipers are inexpensive; however, they are suited primarily for use in wiping aqueous materials and are not entirely satisfactory for use with oil. Paper wipers also are primarily suitable for only a single use and then must be disposed. Cloth wipers, on the other hand, while suitable for wiping both oils and water, are expensive and must be laundered. In addition, unless care is taken in laundering, water absorption rates for cloth wipers can be adversely affected. Non-woven wipers made from rayon, which may also include other ingredients such as pulp, for example, and other synthetic materials, have been available, but in general fail to provide good wiping properties with both oil and water and may entail a cost that prevents disposability except in special applications. Finally, both natural and synthetic sponges are in widespread use for wiping, but are even more expensive.
Examples of prior wipers within these broad classifications are contained in the following U.S. patents which are intended to be representative and not exhaustive: U.S. Pat. No. 3,477,084 to Thomas; U.S. Pat. No. 3,520,016 to Meitner; U.S. Pat. No. 3,546,056 to Thomas; U.S. Pat. No. 3,650,882 to Thomas; and U.S. Pat. No. Re. 27,820 to Politzer et al.
The preparation of polyolefin microfiber webs is also known and described in Wente, Industrial and Engineering Chemistry, Volume 48, No. 8 (1965), pp. 1342-1346, as well as U.S. Pat. No. 3,978,185 to Buntin et al., U.S. Pat. No. 3,795,571 to Prentice, U.S. Pat. No. 3,811,957 to Buntin, and U.S. Pat. No. 4,307,143 to Meitner. The Buntin et al. patent and the U.S. Pat. No. 4,307,143 to Meitner both disclose that meltblown polyolefins are useful as wiping cloths and hydrocarbon absorption material. However, the wipers as described in these publications each are deficient to a significant degree in one or more of the following properties: cost, combined oil and water wiping, clean wiping, physical properties, or durability.
It is an object of the present invention to provide a wiper that is inexpensive to produce.
It is another object of the present invention to provide a wiper that wipes well for both oil and water residues.
It is a further object of the present invention to provide a wiper that enables clean wiping by fully absorbing a liquid material on the first application.
It is a further object of the present invention to provide a wiper that has improved durability over paper wipers and thus can be reused.
It is a further object of the invention to provide a wiper that exhibits durable hydrophilicity, i.e., the wiper retains its absorbency after multiple uses.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.